It is commonly known to use a check valve with a closure mechanism consisting of a disc that pivots within the valve body. Check valves are designed to stop flow reversals within a piping system. The disc closure mechanism typically pivots about a hinge that is fully contained in the valve body. Such check valves are disclosed in U.S. Pat. No. 4,054,153 and U.S. Pat. No. 5,341,840.
It has also been commonly known to use an indicator mechanism to show the check valve disc position. Users of check valves desire to verify the position of the valve (open or closed), because lack of flow could indicate a serious condition in the pipeline. Thus, it has been known to attach an indicator mechanism to the pivot point of the disc such that the disc position, i.e. open or closed, can be observed by an external indicator dial. U.S. Pat. No. 5,746,246 discloses this type of indicator. It is also known to check on the position of a check valve using an inductive type proximity switch that is mounted on the valve body with its target mounted internally on the flapper. The target transmits an electric signal indicating when the flapper is open or closed.
Prior position indicators of these types are expensive and complicated, however. As a result, there has been a need to develop a check valve position indicator that has a more simple design. One such design is shown in U.S. Pat. No. 6,152,173. This design includes an indicator assembly comprised of a threaded plug inserted into a threaded hole or threaded box on top of the valve cover, an indicating bracket, and a rod assembly including a rod or rods that extend in both directions from the plug and which moves in relation to the valve disc and is held in the threaded plug by a pivotable spherical element or ball. In operation, the inwardly extending end of the rod is held by a tension spring against the check valve disc. The outwardly extending end of the rod protrudes from the valve cover and terminates near a top end of an indicating plate. When flow develops in the pipeline, the valve disc lifts up and the rod, in turn, is forced to lift via contact with the disc. The outwardly extending end of the rod then pivots downward to show that the valve is “open” by reference to the indicating plate. While the rod is in motion, it is held from translating by the pivotable ball contained in the threaded plug. The ball rotates against non-metallic seals in the plug. While this design addresses the need for a simple position indicator it has several disadvantages. First, because the indicator assembly uses a rod that protrudes from the top of the valve, this design precludes the use of an upper clean-out port. Further, the indicator assembly must be restrained against lateral movement because the pivotable ball can move laterally. Finally, the indicator is not adjustable.
The present invention addresses these disadvantages in the prior art design by providing for a side-mounted valve position indicator